Downtime was a major problem for Twitter in its early years. What was remarkable about the information network's performance during Election Day in the US was how stable the service seemed.

Now, instead of the Fail Whale—the lighthearted icon Twitter displayed when the service was unavailable—it's wrestling with a very different animal. One that "roars" longer and louder, according to Mazen Rawashdeh, a Twitter vice president in charge of infrastructure.

In a blog post, Rawashdeh said that in contrast to previous peaks, Twitter saw a sustained surge of traffic, not a short-lived peak. Twitter averaged just under 10,000 tweets per second for an entire hour from 8:11 to 9:11 Pacific Time on Tuesday night—the period shortly before and after the networks declared Barack Obama the winner of the presidential election—peaking at 15,107 tweets per second. (Those numbers are systemwide, not specific to the US or election-related tweets.)

Rawashdeh says Twitter's engineers are seeing these longer, sustained traffic peaks more and more, and are reengineering its infrastructure to handle them—for example, by eliminating a layer of software that sits between Twitter's mobile clients and its back-end system.

By the way, why is Twitter sharing the technical tricks it's using to keep up with traffic?

We think it serves two main purposes for the company: Reassuring users that they can continue to rely on Twitter during big news events, and enticing potential engineering recruits with the kind of technology problems they might face working at Twitter.